Conjugated linoleic acid (CLA) is a special type of polyunsaturated fat that has received a great deal of interest because of its potential role in health and reducing body fat. In animal studies, CLA supplementation has consistently been shown to reduce body fat. Studies conducted in humans have in some cases confirmed these effects. However, it should be acknowledged that not all CLA studies have shown consistent results.
In one of the studies that examined the effects of CLA on body fat, 52 overweight/obese men and women were randomized into a placebo group or one of four CLA groups that consumed 1.7, 3.4, 5.1 or 6.8 grams per day (divided into 3 equal doses).(1) Body weight and body composition (fat mass and lean body mass) were measured before and after 12 weeks of supplementation. Compared to placebo, three of the CLA groups lost significantly more fat mass. The 3.4 g/day group lost almost 4 pounds of fat and the 6.8 g/day CLA group lost almost 3 pounds of fat. The 6.8 g/day group also increased lean body mass by almost 2 pounds. The number of subjects in this study was relatively low but it did provide evidence of a favorable effect of CLA on body fat and lean body mass.
Next, I'll describe the results of two studies that involved a larger number of subjects which found similar benefits of CLA on body composition.
One-year study shows fat loss and lean mass increases
There were essentially no changes in body weight, fat mass or lean body mass in the placebo group.
There was a small weight loss of 2.4 pounds in the CLA group. There was also a significant 3.7 pound reduction in fat mass for the CLA group, as well as a significant 1.5 pound increase in lean body mass. Thus, without any dietary or exercise intervention, simply supplementing with 3.6 grams of CLA a day promoted loss in body weight and fat while increasing lean body mass.During weight regain, CLA increases lean muscle gains and increases your metabolic rate
Initially, a total of 54 men and women were submitted to a structured 3-week low-calorie diet to induce weight and fat loss. No supplementation was provided during this period. Then subjects went back to their normal diet and were divided into either a low dose (1.8 g CLA/day), a high dose (3.6 g CLA/day), or a corresponding placebo group. Doses were taken at breakfast, lunch and dinner for a total of 13 weeks. Body weight, body composition (using very accurate underwater weighing), and resting metabolic rate were determined at the start of the study (weekk 0), after the 3 week weight loss phase (week 3), and after 13 weeks of supplementation (week 16).
The results were somewhat surprising but favorable for CLA. As expected, subjects lost weight at week 3 (average 6.9%), which was associated with reduced fat mass, lean body mass, and metabolic rate. After 13 weeks of supplementation, some of the weight was regained in all groups as expected. CLA supplementation did not affect the amount of weight or fat regained, but both low- and high-dose CLA supplementation significantly increased regain of lean body mass compared to placebo. The increase in lean body mass also resulted in a significant increase in metabolic rate in the CLA groups. During the weight regain, metabolic rate increased by a little more than 200 kcal/day in the CLA group compared to about 140 kcal/day in the placebo group. The results suggest that CLA supplementation could be effective during weight maintenance by preventing regain of body fat and increasing lean weight gain and metabolic rate.CLA's effect is independent of diet and exercise
These studies and others show effective doses of CLA to be in the 2 to 4 grams per day range (equals 3 to 5 softgels per day assuming each softgel contains about 750 mg of CLA). Importantly, studies show that these doses are safe and not associated with an increased frequency of significant adverse responses.The need for CLA supplementation